Whitepaper is the thing which describes briefly about that project so if someone doesn't ready to read that then they are just gambling with their money since the quality of the project can be obtained only after deep research about project with all the possible ways.
This might be categorized as an advertisement that always offers goodness, indeed an advertisement does not all work according to what is promoted, but at least there is an effort to achieve that goal, without a good crypto promotion that will not be understood by some of the world community.